Chelus fimbriatus, the mata mata, is a member of Pleurodira (side-necked turtles). Within Pleurodira it is a member of Chelidae, a clade found today only in South America and Australia (see Gaffney website for more information on pleurodires and cryptodires). Gaffney (1977) and Seddon et al. (1997) conducted systematic analyses of recent chelids; Sánchez-Villagra et al. (1995) studied Chelus fimbriatus; and Wood (1976) described Chelus fossils.

The skeleton of Chelus fimbriatus has not been described or figured in its entirety. Gaffney (1979) produced the only labeled figures of the skull (figs. 23, 70, 88, 144, and 150); other figures of the skull may be found in Boulenger (1889: fig. 52; includes jaw) and Pritchard and Trebbau (1984: fig 16). Boulenger (1889: fig. 53) and Pritchard and Trebbau (1984: fig. 16) also figured the unlabeled shell of Chelus; current shell terminology can be found in Zangerl (1969). Rütimeyer (1873: plate 8, fig. 5) provided an excellent internal view of the carapace; Hoffstetter and Gasc (1969: fig. 13) figured all of the cervical vertebrae; and Kasper (1903: plate 1) figured the atlas-axis complex of Chelus and other chelids.

About the Species

This specimen was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Adam Summers of the Department of Ecology and Evolutionary Biology, University of California, Irvine. Funding for scanning was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of The University of Texas at Austin.

About this Specimen

The head of the specimen was scanned by Matthew Colbert on 26 November 2001 along the coronal axis for a total of 515 1024x1024 pixel slices. Each slice is 0.2464 mm thick, with an interslice spacing of 0.2464 mm and a field of reconstruction of 105 mm.

To the left is an example of a reduced slice through the braincase of Chelus. Click on the thumbnail for an unreduced version.

About the Scan

Literature

Boulenger, G. A. 1889. Catalogue of the chelonians, rhynchocephalians and crocodiles in the British Museum (Natural History), London, printed by order of the Trustees of the British Museum (Natural History). Taylor and Francis, London. 311 pp.